Method and apparatus for diverting fluid flow

ABSTRACT

Fluid amplifier apparatus comprising a power nozzle for issuing a deflectable power stream, fluid receiver means for receiving a variable portion of the power stream, and control means for issuing a control stream in a variable transverse direction relative to the power stream so that a variable portion of the control stream intercepts the power stream, thereby varying the received portion thereof. The control means may comprise a series of nozzles, each adapted to issue a fluid stream, a variable portion of which, depending on the deflection thereof, transversely impinges on the next succeeding fluid stream causing its deflection. Single-ended and differential output embodiments are disclosed.

United States Patent Inventor [72] John G. Rupert St. Anthony Village, Minn.

[21] Appl. No. 1,107

[22] Filed Jan. 7, 1970 [45] Patented Dec. 14, 1971 [73] Assignee Honeywell Inc.

Minneapolis, Minn.

[54] METHOD AND APPARATUS FOR DIVERTING FLUID FLOW 12 Claims, 3 Drawing Figs.

[52] U.S. Cl 137/13, 137/81.5

[51] Int. Cl FlSc l/l4 E [50] Field ofSearch I37/8l.5,

[56] References Cited UNITED STATES PATENTS 13,155,825 11/1964 Boothe 137/8l.5 1' 3,208,464 9/1965 Zilberfarb 1 37/8 I .5 M

3,409,034 11/1968 Rose 137/815 3,416,551 12/1968 Kinner 137/815 3,472,256 10/1969 Hartmann 137/8l.5 FOREIGN PATENTS 1,347,426 11/1963 France 137/815 Primary Examiner-William R. Cline Attorneys-Charles .l. Ungemach, Ronald T. Reiling and Charles L. Rubow ABSTRACT: Fluid amplifier apparatus comprising a power nozzle for issuing a deflectable power stream, fluid receiver means for receiving a variable portion of the power stream,

and control means for issuing a control stream in a variable transverse direction relative to the power stream so that a variable portion of the control stream intercepts the power stream, thereby varying the received portion thereof. The control means may comprise a series of nozzles, each adapted to issue a fluid stream, a variable portion of which, depending on the deflection thereof, transversely impinges on the next succeeding fluid stream causing its deflection. Single-ended and differential output embodiments are disclosed.

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SHEET 1 0F 2 FIG. I

ENTOR. JOHN .RUPERT ATTORNEY PATENTEumm 3;626;960

sum a nr 2 INVENTOR. JOHN G. RUPERT ATTORN /M 7 Z" I METHOD AND APPARATUS FOR DIVERTING FLUID FLOW BACKGROUND OF THE INVENTION This invention pertains generally to fluid operated apparatus, and more specifically to fluid operated signal amplification devices.

Fluid amplifiers and various other fluidic devices have been known in the art for some time. More recently, relatively complex fluidic circuits and complete fluid systems have been developed. The recent interest in fluid systems design has placed significantly more demanding requirements on fluid amplifiers and basic fluid circuits. These requirements include faster operational speed, higher operating frequency limits, higher efficiency, lower power consumption and decreased size. Further, it is pointed out that the requirement for decreased size necessitates both a decrease in the dimensions of fluid amplifiers alone, and a decrease in the number and dimensions of necessary associated components, such as those required for amplifier compensation.

A typical solution to a system requirement for large amplification of a fluid signal has been the provision of a cascade of conventional fluid amplifiers. In such a cascade, each amplifier accepts a fluid pressure input signal, converts the fluid pressure signal to a flow signal, utilizes the flow signal to deflect a power stream of higher energy than the flow signal, receives a variable portion of the power stream depending on the deflection thereof, and converts the momentum of the received portion of the power stream into a pressure signal suitable for transmission over a relatively long distance to the input of the next succeeding fluid amplifier in the cascade. Each amplifier in the cascade thus provides one stage of signal amplification.

In a cascade of conventional amplifiers, each amplifier includes diffuser means for converting the kinetic energy (momentum) of the received portion of the power stream into a potential energy (pressure) signal so as to allow its transmission over relatively large distances. When the pressure signal reaches a succeeding amplifier, it is again converted into a kinetic energy or momentum signal by a control nozzle. Thus, in a cascade of conventional amplifiers, the fluid signal is basically converted from a momentum signal to a pressure signal and back to a momentum signal between each pair of amplifiers. One disadvantage of a cascade of conventional fluid amplifiers arises because the conversion of a momentum signal to a pressure signal by a diffuser is inefficient. Each such conversion consumes approximately 50 percent of the available power.

A further disadvantage of a cascade of conventional amplifiers arises from the fact that fluid signals must travel relatively large distances within and between the individual amplifiers. The speed of operation of fluid amplification apparatus is directly related to the time required for fluid signals to propagate therethrough. Since the speed of propagation of a fluid signal is relatively slow, the operational speed of such apparatus is greatly afiected by the dimensions of the in dividual elements and interconnecting passages therein. In a conventional amplifier cascade, the distances over which a fluid signal must travel is greatly increased by the necessary interconnecting passages between successive amplifiers.

A further disadvantage of a cascade of conventional fluid amplifiers arises when a feedback network is used therewith. The compensation or signal-shaping desired from a feedback network requires a proper phase relationship between the input and feedback signals. This can be provided for a given frequency by properly dimensioning the feedback passages. However, as the frequency changes, the phase relationship between the input signal and the feedback signal generally varies. This relationship may easily vary until the feedback signal is 180 from the required phase relationship with the input signal. In conventional circuits, compensation to minimize this problem has been provided by utilizing appropriately sized fluidic capacitors in the interconnecting passages and feedback networks. In many circuits these capacitors must be of substantial size, thus disadvantageously increasing the physical size of the circuits. Further large capacitances in these circuits reduce the upper frequency limit at which the circuits can be used.

Thus, it is apparent that a cascade of conventional amplifiers produces severe limitations in a circuit in which it is used. These limitations arise from high-power consumption, slow operating speed, a relating low upper frequency limit and relatively large physical dimensions of the amplifiers and the associated circuitry. These and certain other disadvantages of prior art devices have been avoided in the applicant's unique fluid signal amplification apparatus.

SUMMARY OF THE INVENTION Fluid signal amplification apparatus in accordance with the applicants invention basically comprises a power nozzle for issuing a power stream, a receiver disposed to receive a variable portion of the power stream, means for issuing a first control stream in a variable direction so that a variable portion thereof transversely impinges on the power stream, and means for issuing a second variable control stream in a transverse relationship to the first control stream so as to vary the deflection of the first control stream, thereby varying the deflection of the power stream, and consequently varying the received portion of the power stream. Any control stream may be oriented so that it is nonnally ineffective to act on the next succeeding stream. Alternately, any control stream may be oriented so that all or any part thereof normally impinges on the next succeeding stream. Finally, means for issuing the various streams in apparatus according to the applicant's invention may comprise an asymmetrical arrangement of nozzles substantially entirely on one side of the normal centerline of the power stream, or it may comprise a nozzle arrangement which is symmetrical about this normal centerline.

In accordance with the teachings of the applicant's inven tion, each succeeding stream provides an additional stage of signal amplification. Power loss is reduced by eliminating the requirement for a diffuser and a nozzle for converting kinetic energy to potential energy, and potential energy to kinetic energy between a pair of amplification stages. The operational speed is maximized by minimizing the distances over which fluid signals must travel within and between amplification stages. Since signal transport lags are minimized, the problems created because of variations in the phase relationships between input and feedback signals are minimized. Specifically, this configuration permits the use of smaller feedback elements, and it provides for higher operating frequencies.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional plan view of a first embodiment of a multistage fluid amplifier in accordance with the applicants invention;

FIG. 2 is a view of the embodiment shown in FIG. 1 taken along lines 22; and

FIG. 3 is a sectional plan view of a second embodiment of the applicant's unique multistage fluid amplifier.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 and 2, reference numeral 10 identifies a first embodiment of a fluid amplifier in accordance with the applicants invention. Apparatus 10 comprises a frame 11 shown as having a hollow rectangular cross section. A pair of control ports 12 and 13, a plurality of nozzles 14, l5, l6, l7, and 18, and a receiver 19 are mounted in frame 11, and are thereby maintained in a predetermined spaced relationship with one another. Control ports 12 and 13 are connected to a suitable source 20 of fluid pressure differential control signals by means of conduits 22 and 23. Nozzles 14, 15, I6, 17 and 18 are respectively connected to regulated fluid sources 24, 25, 26, 27 and 28 of successively increasing pressures. The receiver 19 is connected to a suitable pressure transducer 29 by means of a conduit 30.

As a result of being supplied with fluid from fluid sources 24 through 28, nozzles 14 through 18 issue fluid streams illustrated by groups of arrows identified by reference numerals 34, 35, 36 37 and 38. In the absence of external forces, the fluid stream issued by any nozzle is directed along the axis with which the nozzle is aligned. More specifically, under such conditions, stream 34 is directed along axis 44, stream 35 is directed along axis 45, stream 36 is directed along axis 46, stream 37 is directed along axis 47, and stream 38 is directed along axis 48. In the embodiment of FIGS. 1 and 2, axes 44 through 48 lie in a single plane. Further, axis 44 intersects axis 45, axis 45 intersects axis 46, axis 46 intersects axis 47, and axis 47 intersects axis 48. Finally, receiver 19 isaligned with axis 48, and is oriented toward noule 18.

Frame 1 l is provided with covers 50 and 51, thereby enclosing the stream interaction region. The purpose for surrounding the stream interaction region with a protective housing is to shield the region from extraneous fluid currents which can produce spurious deflections of the several streams, thereby producing unwanted signal outputs. Cover 51 is shown provided with vents 53 and 54 for exhausting fluid from the interaction region. The configuration and location shown for these vents is illustrative only. Other suitable configurations and/or locations can be used. The feature of primary importance is that regions of impact between the various streams be covered.

It is pointed out that although the various nozzles are illustrated as having circular cross sections, this feature is not necessary to the applicant's invention. More particularly, it has been found that where this invention is being produced on other than an experimental basis, there are certain advantages to providing nozzles of generally rectangular cross section. Devices embodying passages and nozzles of such configuration lend themselves to fabrication from laminates or by various well-known molding processes.

Signal source 20 may be any suitable source of pressure differential signals. Transducer 29 may also be any suitable device responsive to fluid pressure or flow. Source 20 and transducer 29 may, for example, comprise portions of a larger fluid system such as a fluid operated computer.

In operation, nozzle 14 issues fluid stream 34 generally along axis 44. Fluid stream 34 can be deflected to either side of axis 44 by means of a suitable pressure differential between control ports 12 and 13. In the absence of a pressure differential between control ports 12 and 13, nozzle 14 is shown oriented so that a portion of the stream issuing therefrom impinges transversely on stream 35 issuing from nozzle 15. Stream 35 is shielded from the remaining portion of stream 34 by the structure of nozzle 15.

Nozzle is oriented with respect to nozzle 16 so that if stream 35 is undeflected, no portion thereof impinges on stream 36. However, if stream 35 is deflected by means of stream 34, a portion of stream 35 impinges transversely on stream 36. Similarly, nozzle 16 is oriented with respect to nozzle 17 so that if stream 36 is undeflected, no portion thereof impinges on stream 37. However, if stream 36 is deflected by means of stream 35, a portion thereof impinges transversely on stream 37.

Finally, nozzle 17 is oriented with respect to nozzle 18 so that if stream 37 is undeflected, substantially all of stream 37 impinges transversely on stream 38. Under such conditions, the momentum of stream 37 is sufficient to deflect stream 38 so that substantially no portion thereof enters receiver 19. However, if stream 37 is deflected by means of stream 36, stream 38 is shielded from a portion of stream 37 by means of the structure of nozzle 18. Accordingly, the momentum interchange between streams 37 and 38 is reduced. As a result, the deflection of stream 38 is reduced, and a portion thereof enters receiver 19.

As illustrated in FIG. 1, nozzles 14 through 18 are oriented with respect to one another so that in the absence of a pressure differential between control ports 12 and 13, stream 34 is undeflected and streams 35, 36 37 and 38 are deflected a predetennined amount. This predetermined deflection of any one of streams 35, 36, 37 and 38 is less than the maximum deflection which can be produced in the streams. It is also pointed out that each of streams 34 through 38 is capable of proportional deflection. That is, the amount of deflection is dependent on the relative momenta of the stream being deflected and stream, or portion thereof, causing such deflection. Consequently, the deflection of any of 38, 35 through 38 is dependent on the portion of the transverse stream which impinges thereon.

The amount of fluid received by receiver 19 can be continuously varied between zero and a predetermined maximum value by providing appropriate pressure differential control signals between control ports 12 and 13. Specifically, if the pressure at control port 12 is sufficiently greater than the pressure at control port 13, stream 34 will be deflected so that substantially no part thereof impinges on stream 35. Accordingly, stream 35 will be undeflected, and substantially no part thereof will impinge on stream 36. Stream 36 will thus be undeflected. In its undeflected condition, no part of stream 36 impinges on stream 37, and stream 37 is undeflected. In its undeflected state, substantially all of stream 37 impinges on stream 38 and stream 38 is deflected so that substantially no part thereof enters receiver 19.

Similarly, if the pressure at control port 13 is sufficiently greater than the pressure at control port 12, stream 34 will be deflected so that substantially all of the stream impinges transversely on stream 35, thus deflecting stream 35 so that substantially the entire stream impinges transversely on stream 36. Stream 36 is consequently deflected so that substantially the entire stream impinges on stream 37, thus deflecting stream 37 so that substantially no part thereof impinges on stream 38. Stream 38 is thus undeflected and a maximum portion thereof enters receiver 19.

It is pointed out that nozzles l5, l6 and 17 comprise a series of nozzles, each adapted to issue a deflectable fluid stream a variable portion of which, depending on the deflection thereof, transversely impinges on the next succeeding fluid stream causing its deflection. Control ports 12 and 13 and nozzle 14 comprise deflection means operable in response to an input signal to variably deflect the fluid stream issued from the first nozzle in the series. The stream issued; by the last nozzle in the series operates to deflect the stream issued by a power nozzle (nozzle 18) so as to vary the portion thereof received in a receiver.

It should further be noted that one stage of amplification is provided by each nozzle. This is in accordance with the principles of fluid signal amplification utilized in prior art momenturn interchange fluid amplifiers. Specifically, these principles teach that a fluid stream can be deflected by another fluid stream of lesser momentum. The applicant has utilized this principle to provide a multistage fluid signal amplification device capable of very high amplifications. Further, it can be seen that this device is embodied in a very compact structure. Such compact structure is made possible by eliminating the diffusers and interconnecting conduits between successive stages. In addition to the advantages inherently arising from small device dimensions, this design minimizes the distances over which fluid signals must travel, thereby minimizing signal transport delays. Further, as hereinbefore discussed, minimizing signal transport delays allows for higher operating frequencies and permits the use of smaller and less complex feedback networks for compensation and signal shaping purposes.

Referring now to FIG. 3, reference numeral 60 identifies a second embodiment of fluid signal amplification apparatus in accordance with the applicant's invention. Apparatus 60 comprises a frame 61 shown as having a hollow rectangular cross section. A pair of control ports 62 and 63, a plurality of nozzles 64, 65, 66, 67, 68, 69 and 70, and a pair of receivers 71 and 72 are mounted in frame 61, and are thereby maintained in a predetermined spaced relationship relative to one another. Control ports 62 and 63 are connected to a suitable source 73 of fluid pressure differential control signals by means of conduits 74 and 75. Source 73 may, for example, be a portion of a larger fluid operated system or circuit.

Nozzles 64 and 65 are connected to regulated fluid sources 84 and 85 which supply fluid at a first predetermined pressure. Nozzles 66 and 67 are connected to regulated fluid sources 86 and 87 which supply fluid at a second predetermined pressure, preferably higher than the first predetermined pressure. Nozzles 68 and 69 are connected to regulated fluid sources 88 and 89 which supply fluid at a third predetermined pressure, preferably higher than the second predetermined pressure. Nozzle 70 is connected to a regulated fluid source 90 which supplies fluid at a fourth predetermined pressure, preferably higher than the third predetermined pressure.

Receivers 71 and 72 communicate with conduits 91 and 92 respectively, which supply fluid to ends 93 and 94 of a cylinder 95 so that a piston 96 therewithin will move in response to a pressure differential developed thereacross. Receivers 71 and 72 are provided with diffuser sections 76 and 77 respectively. The purpose for diffuser section 76 and 77 is to facilitate the conversion of kinetic energy in the portions of the stream from nozzle 70 flowing into receivers 71 and 72 into potential energy (pressure) for transmission over a relatively long distance to utilization apparatus (specifically,

cylinder 95). g

A cover plate 99 similar to cover plate 51 is attached to frame 61 so as to shield the stream issued by the several nozzles from the influences of extraneous fluid currents. A second cover plate (not shown), similar to cover plate 99, is attached to the opposite side of frame 61. Vents 100 and 101, and similar vents in the second cover plate, permit fluid to be exhausted from within the housing surrounding the stream interaction region.

Nozzles 64 through 70 are respectively aligned with axes 104 through 110. In the embodiment shown, axes 104 through 110 lie in a single plane. Fluid supplies 84 through 90 cause nozzles 64 through 70 to issue fluid streams along the axes 104 through 110 respectively. If undeflected, the stream from nozzle 64 impinges on the structure of nozzle 66, and no part thereof impinges on the stream from nozzle 66. Similarly, if undeflected, no part of the stream issuing from nozzle 66 impinges on the stream issuing from nozzle 68. Similarly, if undeflected, no part of the stream from nozzle 68 impinges on the stream from nozzle 70.

Apparatus 60 is symmetrical about axis 1 10. Consequently, if undeflected, no part of the stream issuing from nozzle 65 impinges on the stream issuing from nozzle 67, no part of the stream issuing from nozzle 67 impinges on the stream issuing from nozzle 69, and no part of the stream issuing from nozzle 69 impinges on the stream issuing from nozzle 70. Under such conditions, equal portions of the stream issuing from nozzle 70 are received in receivers 71 and 72. Consequently, equal pressures are developed in diffuser sections 76 and 77. These equal pressures are transmitted to ends 93 and 94 of cylinder 95, thereby maintaining piston 96 in its existing position.

Streams issuing from nozzles 64 and 65 can be variably deflected by means of variable momentum streams issuing from control ports 62 and 63 respectively. Control ports 62 and 63 are oriented so that streams issuing therefrom transversely impinge on streams from nozzles 64 and 65. The momentum of streams from ports 62 and 63 can be varied by signals from source 73.

lt is pointed out that no deflection of the stream issued from nozzle 70 will occur in the event of symmetrical deflection of the streams issuing from corresponding nozzles on opposite sides of axis 110. Specifically, if source 73 provides streams of equal momenta from ports 62 and 63, the streams from nozzles 64 and 65 will be deflected by equal amounts thereby resulting in equal deflections of the streams from nozzles 66 and 67. This condition, in turn, results in equal deflection of the streams from nozzles 68 and 69. Streams from nozzles 68 and 69 then produce equal and opposite deflection forces on the stream issuing from nozzle 70, and no net deflection of the stream from nozzle 70 results. Accordingly, the stream from nozzle 70 is received in equal portions by receivers 71 and 72.

A net deflection of the stream from nozzle 70 results as follows. Assume that signal source 73 produces a fluid pressure differential signal such that the momentum of the stream issuing from port 62 is greater than the momentum of the stream issuing from control port 63. The stream from nozzle 64 is, consequently, deflected to a greater extent than the stream from nozzle 65. Accordingly, the portion of the stream from nozzle 64 which impinges transversely on the stream from nozzle 66 is greater than the portion of the stream from nozzle 65 which impinges transversely on the stream from nozzle 67. This results in greater deflection of the stream from nozzle 66 than deflection of the stream from nozzle 67. There is a corresponding greater deflection of the stream from nozzle 68 than deflection of the stream from nozzle 69. As a result, the portion of the stream from nozzle 68 which impinges on the stream from nozzle 70 is greater than the portion of the stream from nozzle 69 which opposingly impinges on the stream from nozzle 70. The stream from nozzle 70 is thus deflected toward receiver 72. A correspondingly greater pressure is developed in diffuser section 77 than in diffuser section 76. The pressure in difiuser section 77 is transmitted to end 94 of cylinder 95, thus displacing piston 96. in a similar manner, if signal source 73 provides a higher momentum stream from control port 63 than from control port 62, the stream from nozzle 70 will be deflected toward receiver 71.

As indicated in connection with amplifier 10, each succes sive nozzle in amplifier 60 provides an additional stage of amplification. In accordance with the foregoing description, it is apparent that although specific numbers of amplification stages are shown in the illustrated embodiments, either more or fewer amplification stages can be provided to suit the requirements of particular applications. it should be noted that both single-ended and differential output devices have been disclosed. It is pointed out that although both of the illustrated embodiments employ differential input signal means, a single-ended input can equally as well be used. It is further pointed out that it is notnecessary to the applicants invention that the streams from all nozzles operate in a single plane. Embodiments in which the stream from a given nozzle is deflected in a plane transverse to the plane of deflection of the stream on which it impinges are also within the scope of the applicants invention. In addition, although the only specifically illustrated input means for initially deflecting a fluid stream is another variable momentum stream, it should be understood that mechanical means, such as a moveable nozzle, can equally as well be utilized to perform this function.

Finally, it should be noted that the disclosed embodiments employ nozzles whose streams normally totally impinge on the streams from succeeding nozzles, nozzles no part of whose streams normally impinge on the streams from succeeding nozzles, and nozzles a portion of whose streams normally impinge on streams from succeeding nozzles. It will be apparent that a given device may employ a series of nozzles having any desired combination of these operations. The particular configuration chosen is dictated only by the requirements of the application in which the amplifier is used.

As in the embodiment of FIGS. 1 and 2, the embodiment of FIG. 3 results in a very compact amplifier configuration, it eliminates diffusers and transmission conduits between successive stages; it minimizes power loss and maximizes efficiency; and it minimizes the distances over which fluid signals must be transmitted, thus minimizing signal transport delays, increasing operational speed and frequency, and simplifying required feedback networks. Although specific embodiments are shown in detail, these embodiments are only exemplary. A variety of other structural embodiments in accordance with the applicants contemplation and teaching will be apparent to those skilled in the art.

What is claimed is:

1. Fluid amplifier apparatus comprising:

a power nozzle for issuing a power stream along a first axis;

receiver means for receiving a variable portion of the power stream;

stream deflection means for issuing a deflectable stream generally toward the power stream along a second axis, the first and second axes lying in a plane, a variable portion of the deflectable stream, depending on the deflection thereof, impinging on the power stream so as to cause its deflection; and

control means for issuing a variable control stream generally toward the deflectable stream along a third axis lying in the same plane as the first and second axes, so as to vary the deflection of the deflectable stream, thereby varying the portion of the power stream received in said receiver means.

2. The apparatus of claim 1 wherein said control means issues a control stream of variable momentum transversely against the deflectable stream.

3. The apparatus of claim 1 wherein said stream deflection means issues first and second oppositely varying deflectable streams, difi'erentially variable portions of which transversely impinge on opposite sides of the power stream, thereby varying the portion of the power stream received in said receiver thereto; and fluid-actuated means connected to said receiver means for actuation by fluid received in said receiver means.

5. The apparatus of claim 1 wherein said control means issues the control stream in a variable direction in said plane so that a variable portion thereof intercepts the deflectable stream.

6. The apparatus of claim 5 wherein said stream deflection means issues the deflectable stream in a variable direction so as to intersect the first axis at a point which is variable along the axis between limits on opposite sides of said power noule,

7. The apparatus of claim 5 wherein the deflectable stream is normally issued toward the power nozzle and is thus normally ineffective to act on the power stream.

8. The apparatus of claim 5 wherein the deflectable stream is normally issued in a direction effective to act on the power stream.

9. A method of amplifying a fluid signal, which comprising:

issuing a deflectable power fluid stream along a first axis;

receiving a portion of the power fluid stream, the received portion being dependent on the amount of deflection thereof;

issuing a first variable control stream generally toward the power fluid stream along a second axis, the first and second axes lying in a plane, so that a variable portion of the first variable control stream, depending upon the deflection thereof, intercepts the power fluid stream, thereby varying the received portion thereof;

issuing a second variable control stream generally toward the first variable control stream along a third axis lying in the same plane as the first and second axes, so as to vary the deflection of the first variable control stream in said plane; and

controlling the second variable control stream in accordance with an input signal so as to vary the direction of the first variable control stream, thereby varying the portion thereof which impinges on the power fluid stream.

10. The method of claim 9 wherein the step of controlling the second variable control stream comprises varying the momentum thereof.

11. The apparatus of claim 9 wherein the first variable control stream is normally issued toward said power nozzle, and is thus normally ineffective to act on the power fluid stream.

12. The apparatus of claim 9 wherein the first variable control stream is normally issued in a direction effective to act on the power fluid stream.

i 1C it l 

2. The apparatus of claim 1 wherein said control means issues a control stream of variable momentum transversely against the deflectable stream.
 3. The apparatus of claim 1 wherein said stream deflection means issues first and second oppositely varying deflectable streams, differentially variable portions of which transversely impinge on opposite sides of the power stream, thereby varying the portion of the power stream received in said receiver means.
 4. The apparatus of claim 1 further including signal means connected to said control means for supplying input signals thereto; and fluid-actuated means connected to said receiver means for actuation by fluid received in said receiver means.
 5. The apparatus of claim 1 wherein said control means issues the control stream in a varIable direction in said plane so that a variable portion thereof intercepts the deflectable stream.
 6. The apparatus of claim 5 wherein said stream deflection means issues the deflectable stream in a variable direction so as to intersect the first axis at a point which is variable along the axis between limits on opposite sides of said power nozzle.
 7. The apparatus of claim 5 wherein the deflectable stream is normally issued toward the power nozzle and is thus normally ineffective to act on the power stream.
 8. The apparatus of claim 5 wherein the deflectable stream is normally issued in a direction effective to act on the power stream.
 9. A method of amplifying a fluid signal, which comprises: issuing a deflectable power fluid stream along a first axis; receiving a portion of the power fluid stream, the received portion being dependent on the amount of deflection thereof; issuing a first variable control stream generally toward the power fluid stream along a second axis, the first and second axes lying in a plane, so that a variable portion of the first variable control stream, depending upon the deflection thereof, intercepts the power fluid stream, thereby varying the received portion thereof; issuing a second variable control stream generally toward the first variable control stream along a third axis lying in the same plane as the first and second axes, so as to vary the deflection of the first variable control stream in said plane; and controlling the second variable control stream in accordance with an input signal so as to vary the direction of the first variable control stream, thereby varying the portion thereof which impinges on the power fluid stream.
 10. The method of claim 9 wherein the step of controlling the second variable control stream comprises varying the momentum thereof.
 11. The apparatus of claim 9 wherein the first variable control stream is normally issued toward said power nozzle, and is thus normally ineffective to act on the power fluid stream.
 12. The apparatus of claim 9 wherein the first variable control stream is normally issued in a direction effective to act on the power fluid stream. 